How do you solve 2r2+r14=0 using the quadratic formula?

1 Answer
Dec 26, 2016

The two solutions are r=1+1134 and r=11134

or r=2.4075 and r=2.9075

Explanation:

Since this question is given in standard form, meaning that it follows the form: ax2+bx+c=0, or ar2+br+c=0 in this case, we can use the quadratic formula to solve for x:
https://mathbitsnotebook.com/Algebra1/Quadratics/QDquadform.htmlhttps://mathbitsnotebook.com/Algebra1/Quadratics/QDquadform.html

I think it's worthwhile to mention that a is the number that has the x2 term associated with it. Thus, it would be 2r2 for this question.b is the number that has the x variable associated with it and it would be 1r, and c is a number by itself and in this case it is -14.

Now, we just plug our values into the equation like this:

r=(1)±(1)24(2)(14)2(2)

r=1±1+1124

r=1±1134

For these type of problems, you will obtain two solutions because of the ± part. So what you want to do is add -1 to 113 together and divide that by 4:

r=1+1134
r=9.63014=2.4075

Now, we subtract 113 from -1 and divide by 4:

r=11134
r=11.63014=2.9075

Therefore, the two possible solutions are:
r=2.4075 and r=2.9075